在Android中使用音量键更改亮度屏幕

Question

我想用音量键更改屏幕的亮度。我使用此代码，但它不起作用：

@Override 
    public boolean onKeyDown(int keyCode,KeyEvent keyEvent){ 
     WindowManager.LayoutParams layout = getWindow().getAttributes(); 

     if(keyEvent.getAction() == KeyEvent.ACTION_DOWN){ 
      switch (keyCode){ 
       case KeyEvent.KEYCODE_VOLUME_DOWN: 
        layout.screenBrightness -= 0.1; 
        getWindow().setAttributes(layout); 
        break; 
       case KeyEvent.KEYCODE_VOLUME_UP: 
        layout.screenBrightness += 0.1; 
        getWindow().setAttributes(layout); 
        break; 
      } 

     } 
     return super.onKeyDown(keyCode , keyEvent); 
    } 

当我按音量键向下/向上铃声音量改变？

Answer 1

试试这个：

@Override 
public boolean dispatchKeyEvent(KeyEvent event) { 
int action = event.getAction(); 
int keyCode = event.getKeyCode(); 
    switch (keyCode) { 
    case KeyEvent.KEYCODE_VOLUME_UP: 
     if (action == KeyEvent.ACTION_UP) { 
      //TODO 
     } 
     return true; 
    case KeyEvent.KEYCODE_VOLUME_DOWN: 
     if (action == KeyEvent.ACTION_DOWN) { 
      //TODO 
     } 
     return true; 
    default: 
     return super.dispatchKeyEvent(event); 
    } 
} 

这是一个从here。下次尝试更好地搜索。

Answer 2

@Override 
public boolean dispatchKeyEvent(KeyEvent event) { 
int action = event.getAction(); 
int keyCode = event.getKeyCode(); 
    switch (keyCode) { 
    case KeyEvent.KEYCODE_VOLUME_UP: 
     if (action == KeyEvent.ACTION_UP) { 

       brightness+=10; 
      if (brightness > 100) brightness = 100; 
     } 
     return true; 
    case KeyEvent.KEYCODE_VOLUME_DOWN: 
     if (action == KeyEvent.ACTION_DOWN) { 
      brightness-=10; 
      if (brightness < 0) brightness=0; 
     } 
     return true; 
    default: 
     return super.dispatchKeyEvent(event); 
    } 
} 

功能

private void setBrightness() { 
    Window w = getWindow(); 
    WindowManager.LayoutParams lp = w.getAttributes(); 
    lp.screenBrightness = (float)brightness/100; 
    if (lp.screenBrightness<.01f) lp.screenBrightness=.01f; 
    w.setAttributes(lp); 
    updateTextLabel(); 
}